Co-pending patent applications, Ser. Nos. 165,815 and 165,816, now U.S. Pat. Nos. 4,305,257 and 4,300,355, respectively, disclose and claim processes for producing in-line flowable slush mixtures. Specifically, in U.S. Pat. No. 4,300,355 the claimed process comprises flowing a stream of liquid, e.g. water, through a closed conduit of the slush making device, which conduit makes a tee joint with the body portion of the slush making apparatus, introducing a liquid cryogen, e.g. LIN, into the flowing water so that the water flows concurrently with the LIN to form the slush mixture which is discharged from the conduit. The criticalities of this process and that of the present process, as set forth in this U.S. Pat. No. 4,300,355 application and incorporated herein by reference, are that the temperature of the water into which the LIN is introduced must be about 2.degree. F. above the freezing point of water to about 10.degree. above, the contact time between the introduction of LIN and the discharge of the slush is maintained from about 0.001 to about 10 seconds, the superficial velocity of the water in the device is stated as being at least about 1.5 feet per second and finally the weight ratio of the LIN to water must be maintained from about 0.025:1 to about 2:1.
The apparatus used for carrying out both of the processes of these co-pending applications comprise an elongated cylindrical slush lance, a water inlet leg connected to the lance at a right angle thereto to form a conventional tee ("T") at the end of the lance remote from the slush discharge. Extending into the lance from a sealed end remote from the discharge and disposed coaxially with the lance is the LIN inlet line which is in sealing engagement with the sealed end.
It has been found that while operating within the scope of the process parameters claimed in these two co-pending applications, a great improvement occurs over the prior art apparatus disclosed in these applications and in U.S. Pat. Nos. 3,672,182 and 3,771,718.
The prior art "T" lance design suffers from water backing up and freezing in the cryogen or LIN inlet line and freezing the LIN solenoid valve in the open position. In addition the liquid in the dead space between the sealed end and the right angle "T" joint of the water inlet freezes, which results in a rather catastrophic failure of the entire slush making system.